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Cellular injury and adaptation

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Pathology, Cellular injury and adaptation.

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Cellular injury and adaptation

  1. 1. Antecedents Group no. 01 Group Members: Rana Ahmed (PHA-14001) Mahfujul Hasan (PHA-14002) Shahida Yeasmin Sima (PHA-14005) Shamima Akter Sumi (PHA-14007) 14 April 2019 1
  2. 2. Contents Introduction to Pathology Definition Father of Modern Pathology Scope Core aspects Cellular Injury and Adaptation Stages of the cellular response Adaptation Hypertrophy Hyperplasia Atrophy Metaplasia Cell injury Intracellular Accumulations 14 April 2019 2
  3. 3. What Is Pathology • Pathology is the study (logos) of diseases (pathos). • The study of the structural, biochemical and functional changes in cells, tissues and organs that underlie diseases. • It attempts to explain sign and symptoms by use of Molecular Microbiologic Immunologic Morphologic techniques 14 April 2019 3
  4. 4. Rudolf Virchow Father of Modern Pathology “Virtually all forms of tissue injury starts with molecular or structural alterations in CELLS” 1821-1902 14 April 2019 4
  5. 5. The Scope of Pathology Scientific knowledge about human diseases from observations on patients or by from experimental studies. Explain the whys and wherefores of signs and symptoms expressed. It offers clinical care and therapy. It serves as the bridge between basic sciences and clinical medicine. Pathology is the foundation for all medicine. 14 April 2019 5
  6. 6. Core aspects of pathology There are four aspects of diseases process that form the core of pathology. These are following- 1. Etiology 2. Pathogenesis 3. Molecular and morphological changes 4. Clinical manifestations 14 April 2019 6
  7. 7. Etiology Pathogenesis Morphological changes Clinical manifestations 1. Genetics  Inherited mutation  Diseases gene mutation 2. Non-genetics  Infectious  Nutritional  Physical  chemical 14 April 2019 7
  8. 8. Etiology Pathogenesis Morphological changes Clinical manifestations  Mechanism of its developments.  Sequences of events in the response of cells or tissues to the etiologic agents.  from the initial stimulus to the ultimate expression of the diseases. 14 April 2019 8
  9. 9. Etiology Pathogenesis Morphological changes Clinical manifestations  Molecular and Morphologic changes refer to the structural alterations in cells or tissues that are either characteristic of a disease or diagnostic of an etiologic process. 14 April 2019 9
  10. 10. Etiology Pathogenesis Morphological changes Clinical manifestations  The end results of genetic, biochemical and structural changes in cells and tissues are functional abnormalities, which lead to the clinical manifestations (symptoms and signs) of disease, as well as its progress.14 April 2019 10
  11. 11. Stages of the Cellular Responses Fig: Stages of the cellular response to stress and injurious stimuli 14 April 2019 11
  12. 12. Adaptation  Adaptations are reversible changes in the size, number, phenotype, metabolic activity or functions of cells in response to changes in their environment.  Four types of adaptation are occurred- • Hypertrophy • Hyperplasia • Atrophy • Metaplasia 14 April 2019 12
  13. 13. Hypertrophy • Hypertrophy is an increase in the size of cells resulting in an increase in the size of the organ. • There are no new cells, just large cells. • Hypertrophy can be physiologic or pathologic. 14 April 2019 13
  14. 14. Example Pathologic hypertrophy Cardiac enlargement that occurs with hypertension or aortic valve disease. Physiologic hypertrophy  Bulging muscles of bodybuilders. 14 April 2019 14
  15. 15. Physiologic hypertrophy Enlargement of the uterus during pregnancy 14 April 2019 15
  16. 16. Mechanisms of Hypertrophy Hypertrophy is the result of increased production of cellular proteins. 14 April 2019 16
  17. 17. Hyperplasia • Hyperplasia is an increase in the number of cells in an organ or tissue, resulting in increased mass of the organ or tissue. • Hyperplasia can be physiologic or pathologic. • In both situations, cellular proliferation is stimulated by growth factors that are produced by a variety of cell types. 14 April 2019 17
  18. 18. Types Physiologic hyperplasia 1. Hormonal hyperplasia: The proliferation of the glandular epithelium of the female breast at puberty and during pregnancy. 2. Compensatory hyperplasia: When part of a liver is resected, mitotic activity in the remaining cells begins as early as 12 hours later, eventually restoring the liver to its normal size. 14 April 2019 18
  19. 19. Pathologic Hyperplasia  Most forms of pathologic hyperplasia are caused by excesses of hormones or growth factors acting on target cells.  Example: Endometrial hyperplasia is an example of abnormal hormone induced hyperplasia. 14 April 2019 19
  20. 20. Mechanisms of Hyperplasia Hyperplasia is the result of growth factor, driven proliferation of mature cells. In some cases, by increased output of new cells from tissue stem cells. 14 April 2019 20
  21. 21. Atrophy • Atrophy is reduced size of an organ or tissue resulting from a decrease in cell size and number. • Atrophy represents a reduction in the structural components of the cell. 14 April 2019 21
  22. 22. Common Causes of Atrophy Decreased workload Loss of innervation Diminished blood supply Inadequate nutrition Loss of endocrine stimulation Pressure 14 April 2019 22
  23. 23. Mechanisms of Atrophy Atrophy results from decreased protein synthesis and increased protein degradation in cells. Reduction metabolic activity. Nutrient deficiency activates ubiquitin ligases. Autophagy 14 April 2019 23
  24. 24. Metaplasia • Metaplasia is a reversible change in which one differentiated cell type is replaced by another cell type. • The most common epithelial metaplasia is columnar to squamous, as occurs in the respiratory tract in response to chronic irritation. 14 April 2019 24
  25. 25. Mechanisms of Metaplasia • Reprogramming of stem cells that are known to exist in normal tissues. • The precursor cell differentiated along a new pathway, signaled by cytokines, growth factor and components of the cell in this environment. 14 April 2019 25
  26. 26. Cell injury • If the adaptive capability is exceeded or if the external stress is inherently harmful or excessive, cell injury develops. 14 April 2019 26
  27. 27. Causes of Cell Injury • Oxygen Deprivation • Physical Agents • Chemical Agents and Drugs • Infectious Agents • Immunologic Reactions • Genetic Derangements • Nutritional Imbalances 14 April 2019 27
  28. 28. Biochemical mechanisms of cell injury 14 April 2019 28
  29. 29. Pathologic Effects of Free Radicals 14 April 2019 29
  30. 30. Apoptosis • Apoptosis is a pathway of cell death that is induced by a tightly regulated suicide program in which cells destined to die activate enzymes that degrade the cells own nuclear DNA and nuclear and cytoplasmic proteins. 14 April 2019 30
  31. 31. CAUSES OF APOPTOSIS Apoptosis in Physiologic Situations Apoptosis serves to eliminate cells that are no longer needed and to maintain a steady. It is important in the following physiologic situations: The programmed destruction of cells during embryogenesis Involution of hormone-dependent tissues upon hormone withdrawal Cell loss in proliferating cell populations Elimination of potentially harmful self-reactive lymphocytes Death of host cells that have served their useful purpose 14 April 2019 31
  32. 32. Apoptosis in Pathologic Conditions Apoptosis eliminates cells that are injured beyond repair without eliciting a host reaction, thus limiting collateral tissue damage. DNA damage Accumulation of mis-folded proteins Cell death in certain infections 14 April 2019 32
  33. 33. MORPHOLOGIC AND BIOCHEMICAL CHANGES IN APOPTOSIS • Cell shrinkage • Chromatin condensation • Formation of cytoplasmic blebs and apoptotic bodies • Phagocytosis of apoptotic cells by macrophages. 14 April 2019 33
  34. 34. Necrosis • Necrosis is a form of cell death in which cellular membranes fall apart and cellular enzymes leak out and ultimately digest the cell. 14 April 2019 34
  35. 35. Necrosis and Apoptosis 14 April 2019 35
  36. 36. Intracellular Accumulations • Under some circumstances, cells may accumulate abnormal amounts of various substances, which may be harmless or may cause varying degrees of injury. • The substances fall into two categories: Normal cellular constituents ex: Water, lipids, proteins etc. Abnormal substances ex: Products of infectious agents, abnormal synthesis/metabolism. 14 April 2019 36
  37. 37. Mechanisms of intracellular accumulation 1. Abnormal metabolism 2. Mutations causing alterations in protein folding and transport 3. A deficiency of critical enzymes 4. Inability to degrade phagocytosed particles 14 April 2019 37
  38. 38. Various components of intracellular accumulation A. Depositions of lipids a. Fatty change b. Cholesterol deposition B. Deposition of proteins C. Deposition of glycogens D. Deposition of pigments E. Pathologic calcifications a. Dystrophic calcification b. Metastatic calcification 14 April 2019 38
  39. 39. THANK YOU 14 April 2019 39
  40. 40. 14 April 2019 40
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Pathology, Cellular injury and adaptation.

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